Highly bioactive and lowly cytotoxic Si-based NiOOH nanoflowers targeted against various bacteria, including MRSA, and their potential antibacterial mechanism

Abstract With the emergence of new drug-resistant microorganisms, the development of effective antimicrobial agents is urgently required. Core-shell-structured nanomaterials have received considerable attention as antibacterial agents. We prepared a bioactive core-shell-structured silicon-based NiOOH nanoflower (Si@NiOOH) targeted against various bacteria using a modified chemical bath deposition method. Further, we investigated its potential antibacterial mechanism by evaluating electrochemical properties in a redox reaction with ascorbic acid, measuring metal ion release, and analyzing the surface area. The bactericidal rate of Si@NiOOH at 200 μg/ml towards Pseudomonas aeruginosa, Klebsiella pneumoniae, and methicillin-resistant Staphylococcus aureus was as high as 99.9%. Si@NiOOH maintained its original morphology after killing the bacteria and exhibited negligible cytotoxicity towards mouse embryonic fibroblasts. The excellent antibacterial activities of Si@NiOOH are possibly derived from its high surface area, providing a wide active site attached to the cell wall, and the high oxidative potency of the Ni(III) cations existing on its surface. The high antibacterial activity and low cytotoxicity of the nanoflower make it a promising tool for promoting wound healing and for use with medical devices and implants.